Doorsill for electric furnaces



T. J. PETERS May 2, 1944.,

DOOR SILL FOR ELECTRIC FURNACES Filed July 29, 1941 Patented May 2 19 44 UNITED STATES PATENT OFFICE 'DO'ORSILL FOR; ELECTRIC FURNACES Tom James Peters, Chicago, 111.

Application July 29, 1941,'Serial No. 404,558

2 Claims.

This invention relates to door sills'for metallurgical furnaces and, particularly, 'to an improved door sill for'slagging doors of electric furnaces and the like.

In electric furnaces for the making steel'there is usually provided in the side thereof an opening for withdrawing the slag therefrom and a door for closing the same. There is also provided a sill upon which the door is adapted to rest when it is in its closed position. Heretofore, the sill was usually made of a solid piece of steel, usually a casting, suitably attached to the side of the furnace. When the slag was removed from the furnace, it passed over the sill and such solid steel sills were rapidly washed away during the slag-off period, thus requiring a frequent replacement thereof. In fact, it was necessary to replace such sills about once a week. Such replacement of these sills was not only expensive but tedious and inconvenient.

Accordingly, it is one of the objects of the present invention to provide an improved door sill for electric furnaces and the like which is simple and inexpensive in its construction and maintenance and one which has a relatively long life.

It is another object of the invention to provide an improved door sill for electric furnaces having a relatively high coefficient of heat conductivity and thus eliminating the danger of deterioration thereof by the slag passing thereover.

It is a further object of this invention to provide an insert member for the sills of electric furnaces and the like over which the slag is adapted to pass therefrom, which has a relatively high coeflicient of heat conductivity and with which there is arranged means for cooling the same.

Various other objects and advantages of this invention will become more apparent during the course of the following specification and will be particularly pointed out in the appended claims.

In the accompanying drawing there is shown, for the purpose of illustration, an embodiment which my invention may assume in practice.

In the drawing:

Figure l is a horizontal cross-sectional view taken through a portion of a furnace, illustrating the application of my invention thereto;

Figure 2 is a vertical cross-sectional view taken on the line IIII of Figure 1;

Figure 3 is a plan view of the door sill embodying my invention;

Figure 4 is a cross-sectional view taken on the line IVIV of Figure 3; and

Figure 5 is an end view of the door sill.

Referring more particularly to the drawing, there is shown for the purpose of illustration merely the upper portion of an electric furnace showing the improved door sill of my invention incorporated therewith. Such a furnace consists generally of a side wall 2 having a substantially rectangular-shaped opening 73 arranged therein adjacent the top of the same for withdrawing therethrough the slag from the top of the molten metal within the furnace. There is positioned opposite the opening 3 for closing the same a door i which is arranged for movement in a vertical plane in guideways 5 secured to the outer side wall of the furnace. There is provided preferably a chain 6 which is suitably arranged over a pulley i mounted above the door for operating the same.

According to the present invention, there is arranged on the outer side wall of the furnace outside the opening 3 and directly below the door 4 a sill member 8 upon which the door is adapted to rest when it assumes a closed position over the opening 3. The sill is preferably made of three parts or segments with two of these parts being identical and positioned to either side of the center of the opening 3 so as to provide a space 9 therebetween. The identical parts or end portions Hi of the sill are preferably steel castings which are securely fixed in a suitable manner to the outer side wall of the furnace.

There is mounted in the opening 9 between the outermost or end segments ill a third segmental member l2 which is adapted to be disposed opposite substantially the center portion of the opening 3 and is adapted to be held in position by means of a pair of cap screws l3 which are screwed through the segmental member I2 into an angle iron member [4 securely arranged on the outer side wall of the furnace. The insert or segmental member i2 consists preferably of a metallic casting having a relatively high coefficient of heat conductivity. It has been found that an insert made of pure copper is most practical for the reason that it has a coeificient of heat conductivity from eight to ten times that of steel. There is arranged within the insert member i2 preferably a substantially U-shaped tubular member, such as a pipe 15 with the ends of the pipe being threaded and extending downwardly from the lower side of the insert member, as shown in Figure 4 of the drawing. The threaded ends of the pipe it are adapted to be connected to a source of fluid supply (not shown) for conveying a cooling fluid therethrough for cooling the insert or segmental member I2.

In removing the slag from the top of the molten metal in the furnace, temporary banks of dolomite or some other suitable refractory material are built up on either side of the insert member I2 opposite the opening 3 so that the slag, in being removed from the furnace, will pass over the copper insert member only. It will be understood it is the practice to tilt the furnace only slightly to effect the removal of the slag, the removal being largely manual. Thus, it will be seen that the furnace operator selects the path of the slag and confines it so that it will pass merely over the insert member I2.

As a result of my invention, it will be seen that there is provided an insert member in which deterioration thereof is caused only by mechanical wear, due to the abrasive action caused by the passage of the slag and slagging tools thereover, and a sill which will not be washed away during the slag-off period as are conventional type cast steel sills now in use. The heat imparted to the insert member by the molten slag as it passes thereover is carried away rapidly enough, due to the cooling pipe arranged therein, so as to prevent the metal of the insert member from reaching its melting temperature. It will also be seen that there is provided a sill member which lasts longer than any sill heretofore proposed or used,

thereby reducing the replacement costs thereof to a minimum.

While I have shown and described one specific embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.

I claim:

1. In combination with a furnace of the class described having an opening arranged in the side thereof for removing slag therefrom and a door for closing said opening, a sill arranged below said opening upon which said door is adapted to rest when movedto its closed position, said sill including an insert member arranged directly opposite said opening and over which the slag is adapted to flow, said insert member comprising a substantially flat relatively thick metallic body member consisting of a solid casting having a relatively high coefiicient of heat conductivity, and means embedded in and cast integral with said body member for conveying a cooling fluid there.- through for cooling the same.

2. The combination as defined in claim 1 wherein the metallic insert member consists of a casting made of substantially pure copper.

TOM JAMES PETERS. 

